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Abstract:

The invention relates to a mineral wool which can dissolve in a
physiological medium, comprising fibres having a chemical composition
that contains the following constituents in the limits defined hereafter
and expressed in percentage by weight, namely: 35 to 75 SiO2; 0 to
12 Al2O3; 0 to 30 CaO; 0 to 20 MgO; 0 to 20 Na2O; 0 to 10
K2O; 0 to 10 B2O3; 0 to 5 Fe2O3; and 0 to 3
P2O5, said mineral wool also comprising at least one phosphorus
compound. The invention is characterised in that a phosphorus compound is
a molecule in which the phosphorus atom(s) are bound to at least one
carbon atom either directly or by means of an oxygen atom.

said mineral wool comprising moreover at least one phosphorus compound,
characterized in that one phosphorus compound is a molecule in which the
phosphorus atom(s) is/are linked, directly or via an oxygen atom, to at
least one carbon atom.

2. The mineral wool as claimed in claim 1, comprising at least one
phosphorus compound chosen from:a) a molecule containing a single
phosphorus atom linked to at least one carbon atom, strictly by means of
an oxygen atom;b) a molecule containing a single phosphorus atom linked
directly to at least one carbon atom.

3. The mineral wool as claimed in claim 2, comprising at least one
phosphorus compound (a) chosen from: a mono-, di- or tri-phosphoric
ester, or an unsubstituted phosphonic or phosphinic ester, the
carbon-based groups of these esters being alkyl, aryl, alkenyl, alkynyl,
acyl or hydroxyalkyl compounds, which may possibly be of oligomeric or
polymeric nature and/or contain one or more heteroatoms chosen from N, O
or S.

4. The mineral wool as claimed in claim 2, comprising at least one
phosphorus compound (b) chosen from an at least partially substituted
phosphonic or phosphinic ester or acid, the various carbon-based groups
of these compounds being alkyl, aryl, alkenyl, alkynyl, acyl or
hydroxyalkyl compounds, which may possibly be of oligomeric or polymeric
nature and/or contain one or more heteroatoms chosen from N, O or S.

5. The mineral wool, comprising at least one phosphorus compound that is a
molecule made up of several compounds of type (a) or (b) as claimed in
claim 2, that are identical or different, linked together by covalent
bonds.

6. The mineral wool as claimed in claim 5, comprising at least one
phosphorus compound that is an oligomer or polymer molecule, of which the
number of constituent units is between 2 and 100.

7. The mineral wool as claimed in claim 5, comprising at least one
phosphorus compound that contains predominantly phosphorus atoms linked
together via a carbon-based entity.

8. The mineral wool as claimed in claim 7, comprising at least one
phosphorus compound that may be represented according to the general
formula (1) below: ##STR00004## in which:n is between 1 and 100;the
substituents R1 to R4 are identical or different, predominantly
carbon-based entities, which may be of oligomeric or polymeric nature
and/or contain one or more heteroatoms chosen from N, O, S or P.

9. The mineral wool as claimed in claim 1, comprising at least one
phosphorus compound that is a phosphonic polyester-type oligomer or
polymer of general formula (2) below: ##STR00005## in which:the chain
length n is between 1 and 100;the substituents R2 and R5 to
R7 are identical or different, carbon-based entities, which may
possibly be of oligomeric or polymeric nature and/or contain one or more
heteroatoms chosen from N, O, S or P.

10. The mineral wool as claimed in claim 8, comprising at least one
phosphorus compound that is a phosphoric polyacid or polyester-type
oligomer or polymer of general formula (3) below: ##STR00006## in
which:the chain length n is between 1 and 100;the substituents R5 to
R8 are identical or different, predominantly carbon-based entities,
which may possibly be of oligomeric or polymeric nature and/or contain
one or more heteroatoms chosen from N, O, S or P.

11. The mineral wool as claimed in claim 4, comprising at least one
phosphorus compound that is obtained by an esterification or
transesterification reaction between acids or esters, that are phosphonic
and phosphoric respectively, and polyols, polyacids or epoxy compounds.

12. The mineral wool as claimed in claim 11, comprising at least one
phosphorus compound that is obtained by reaction between molasses and the
phosphoric or phosphonic acids or esters.

13. The mineral wool as claimed in claim 1, in which the amount of
phosphorus compound, expressed by mass of phosphorus atoms, varies from
0.0005%, especially more than 0.01%, to 1%, especially less than 0.5% of
the total mass of fibers.

14. A method of obtaining the mineral wools as claimed in claim 10,
comprising a fiber-forming step, then a step of introducing, by spraying
or impregnation of a solution, at least one phosphorus compound onto the
surface of said fibers.

17. The method of using at least one molecule in which the phosphorus
atom(s) is/are linked to at least one carbon atom, directly or by means
of an oxygen atom, in order to improve the mechanical properties after
aging in a humid environment of the mineral wools comprising fibers whose
chemical composition comprises the following constituents in the ranges
defined below, expressed as percentages by weight:
TABLE-US-00008
SiO2 35 to 75
Al2O3 0 to 12
CaO 0 to 30
MgO 0 to 20
Na2O 0 to 20
K2O 0 to 10
B2O3 0 to 10
Fe2O3 0 to 5
P2O5 0 to 3.

Description:

[0001]The present invention relates to the field of artificial mineral
wools. It relates more particularly to glass wools intended to be
incorporated into thermal and/or acoustic insulation materials.

[0002]Mineral wools are capable, when certain geometric criteria in terms
of diameter and/or length are observed, of being introduced by inhalation
into the body and especially into the lungs, sometimes all the way to the
pulmonary alveoli. To prevent any pathogenic risk linked to a possible
accumulation of fibers in the body, it has become necessary to make sure
that the fibers have a low "biopersistence", that is to say that they can
be easily and rapidly eliminated from the body. The chemical composition
of the fibers is a major parameter influencing this ability to be rapidly
eliminated from the body, as it plays a significant role in the
dissolution rate of the fibers in a physiological medium. Mineral wools
having high dissolution rates in a physiological medium ("biosoluble"
mineral wools) have therefore been formulated and described in the prior
art.

[0003]The main difficulty consists however in increasing the dissolution
rate of the fibers in a physiological medium while retaining the good
working properties of the end product, especially mechanical strength and
the stability of this mechanical strength during aging in a humid
environment. This latter point is particularly crucial and tricky, since
the two criteria of wet strength and biosolubility are in most respects
contradictory, as they both relate to the ability to be dissolved in a
predominantly aqueous medium.

[0004]Wet-strength requirements are becoming increasingly strict in
numerous applications, in particular in the field of glass wools used to
produce construction components, especially "sandwich" panels, in which
the mineral wool makes up an insulating core between two metal (for
example steel or aluminum) facings. These construction components are
mainly used for roofs and roof cladding, walls and exterior wall
cladding, and walls, partition walls and ceilings located inside the
building envelope. Considering the multiple mechanical stresses to which
they may be subjected, very good compressive, tear and shear strength
properties are demanded. It is important, moreover, that the mechanical
strength, and especially the tear strength, of these products subjected
to ambient humidity do not decline too significantly over time. These
various requirements are in particular specified in the draft of standard
prEN 14509 "Self-supporting double-skin metal-faced insulating sandwich
panels--Factory made products--Specification".

[0005]Patent Application WO 97/21636 describes a type of mineral fiber for
which the resistance to aging in a humid environment is improved due to
deposition of coating of ammonium or alkali metal phosphates or
hydrogenphosphates on the surface of the fibers. This solution is not
however free from disadvantages. It appears in fact that such
phosphorus-based compounds lead to a significant decrease in the
mechanical strength, especially compressive strength and tear strength,
of fibrous products before aging relative to that of uncoated products.
It would seem that the acidity developed by these compounds, probably
originally from the improvement of the aging properties in a humid
environment, is on the other hand prejudicial to the adhesion between the
fibers and the resin-based sizing composition ("binder") during the
polymerization step of the latter.

[0006]One object of the present invention is therefore to obviate these
disadvantages and to improve the aging resistance in a humid environment
of the mineral wools that are soluble in a physiological medium, while
retaining their good mechanical properties before aging (especially in
terms of compressive strength and tear strength).

[0007]One subject of the invention is a mineral wool capable of being
dissolved in a physiological medium comprising fibers whose chemical
composition comprises the following constituents in the ranges defined
below, expressed as percentages by weight:

[0008]said mineral wool comprising moreover at least one phosphorus
compound that is a molecule in which the phosphorus atom(s) is/are
linked, directly or via an oxygen atom, to at least one carbon atom.

[0009]Preferably, each phosphorus compound is a molecule in which the
phosphorus atom(s) is/are linked, directly or via an oxygen atom, to at
least one carbon atom.

[0010]The phosphorus compound is deposited over at least one portion of
the surface of the mineral fibers and therefore does not form a part of
the chemical composition of the glass fiber itself.

[0011]The or each phosphorus compound may be a single molecule, that is to
say, may contain only one phosphorus atom.

[0012]The phosphorus compound according to the invention may then be
characterized in that the single phosphorus atom is directly linked only
to oxygen or hydrogen atoms, that is to say, is linked to at least one
carbon atom only by means of an oxygen atom. It may be, as an example, a
mono-, di- or tri-phosphoric ester, or unsubstituted phosphonic or
phosphinic esters, the carbon-based groups of these esters being alkyl,
aryl, alkenyl, alkynyl, acyl or hydroxyalkyl compounds, which may
possibly be of oligomeric or polymeric nature and/or contain one or more
heteroatoms chosen from N, O or S.

[0013]It may alternatively be characterized in that the single phosphorus
atom is directly linked to at least one carbon atom It may be at least
partially substituted phosphonic or phosphinic esters or acids (that is
to say in which at least one of the hydrogen atoms linked to the
phosphorus atom is substituted by a carbon-based substituent). The
various carbon-based groups of these compounds are alkyl, aryl, alkenyl,
alkynyl, acyl or hydroxyalkyl compounds, which may possibly be of
oligomeric or polymeric nature and/or contain one or more heteroatoms
chosen from N, O or S.

[0014]The or each phosphorus compound according to the invention is,
however, preferably a molecule made up of several identical or different
unitary compounds such as described previously, linked together by
covalent bonds. The phosphorus compound is then preferably an oligomer or
polymer molecule, that is to say, that its structure may be represented
as repeating constituent units. The number of these constituent units is
advantageously between 2 and 100, especially 2 and 50, or even between 2
and 10. In the case of a molecule containing several phosphorus atoms,
the key condition, in accordance with which the phosphorus atoms are
linked to a carbon atom, must be seen as signifying that the large
majority of the phosphorus atoms respect this condition, it being
understood that, in a large molecule, the fact that a small fraction of
the phosphorus atoms do not meet this condition is unable to
substantially change the manner in which the technical problem is solved.

[0015]It may thus be a compound in which the majority (or even all) of the
phosphorus atoms are linked together by an oxygen atom, for example
phosphoric or phosphonic polyester-type compounds.

[0016]It is, however, more advantageous that the majority (or even all) of
the phosphorus atoms be linked together via a carbon-based entity. The
phosphorus compound then contains preferably a majority of phosphorus
atoms linked together by a group comprising at least one carbon atom,
this latter which may be linked directly or by means of an oxygen atom to
at least one of the phosphorus atoms. Such a preferred compound may be
represented according to the general formula (1) below:

##STR00001##

[0017]where:

[0018]n is between 1 and 100, preferably between 1 and 50, especially
between 2 and 10;

[0019]the substituents R1 to R4 are identical or different,
predominantly carbon-based entities, preferably of possibly branched
alkyl, aryl, alkenyl, alkynyl, acyl or hydroxyalkyl type, which may
possibly be of oligomeric or polymeric nature and/or contain one or more
heteroatoms chosen from N, O, S or P. It is preferable that at least one
of these substituents, especially the substituent R1, contains an
oxygen atom linked to the phosphorus atom of the main chain.

[0020]If two of the substituents contain an oxygen atom linked to the
phosphorus atom of the main chain, the phosphorus compound is
advantageously a phosphonic polyester-type oligomer or polymer of general
formula (2) below:

##STR00002##

[0021]When all the substituents contain an oxygen atom linked to the
phosphorus atom of the main chain, another family of preferred phosphorus
compounds is made up of phosphoric polyacid- or polyester-type oligomers
or polymers of general formula (3) below:

##STR00003##

[0022]For these last two types of compounds:

[0023]the chain length n is between 1 and 100, preferably between 1 and
50, especially between 2 and 10;

[0024]the substituents R2 and R5 to R8 are identical or
different, predominantly carbon-based entities, preferably of possibly
branched alkyl, aryl, alkenyl, alkynyl, acyl or hydroxyalkyl type, which
may possibly be of oligomeric or polymeric nature and/or contain one or
more heteroatoms chosen from N, O, S or P. The number of carbon atoms in
each substituent is advantageously between 1 and 15, especially between 2
and 10. A large number of carbon atoms has in fact the disadvantage of
generating a large quantity of carbon-based residues at the time of a
temperature rise, whereas too small a number of carbon atoms may result
in too easy a hydrolysis. The substituents R6 to R8 may also be
hydrogen atoms or a neutralizing base for the phosphoric acid.

[0025]When the chain length n is equal to 1, it is possible that the
R5 and R6 groups be linked together covalently thus forming a
cyclic molecule. When n is greater than 1, some R5, R6 or
R7 groups may be linked together covalently. A preferred phosphorus
compound is thus the product sold under the trademark AMGARD® CT or
CU by Rhodia. It is a mixture of two cyclic phosphonic esters of CAS
numbers 41203-81-0 and 42595-45-9 respectively. The first one is a
phosphonic ester according to the formula (2) with n=1, all the R2
and R7 groups being methyl groups, the R5 and R6 groups
being linked together to form a single alkyl group having 6 carbon atoms.
The second one is an ester of the same type, with however n=2, all the
R2 groups being methyl groups, the two R5 groups being
respectively linked to the R6 and R7 groups to form two C6
alkyl groups.

[0026]The oligomeric or polymeric phosphorus compounds, presented thus far
as linear or cyclic chains, may also be crosslinked networks, the various
predominantly carbon-based substituents being able to be themselves
linked to at least one other phosphorus atom, for example when these
substituents are polyols or polyacids.

[0027]The latter compounds may in particular be obtained by esterification
or transesterification reactions between acids or esters, that are
phosphonic and phosphoric respectively, and polyols (in particular
diols), polyacids (in particular diacids) or else epoxy compounds. Within
this scope, molasses (a by-product of sugar refining) are a particularly
attractive source of polyols or diols due to their low cost. It appeared
that the phosphorus compounds according to the invention were able to be
obtained by reaction between molasses and the phosphoric or phosphonic
acids or esters, this reaction which may even be carried out by
simultaneously spraying the two products on the fibers. Phosphorus-based
starches may also be employed.

[0028]The mineral wool according to the invention may advantageously
comprise a mixture of several phosphorus compounds such as described
previously.

[0029]The point that is common to these compounds which could be termed
"organophosphorus compounds", is the presence of carbon-based compounds
within the phosphorus chain itself. In comparison with the
phosphorus-based compounds described in the prior art, which do not have
carbon-based compounds linked to them, it would seem, without wanting to
be tied by any scientific theory, that the acid buffer function of the
compounds according to the invention manifests itself more diffusely over
time and degrades the adhesion between the fibers and the resin-based
binder much less at the time of curing the latter resin. Thus the better
mechanical properties before aging obtained within the scope of the
present invention could be explained.

[0030]The phosphorus compound according to the invention is preferably
present in an amount greater than or equal to 0.05%, especially 0.1%, and
less than or equal to 5%, especially 3%. This quantity corresponds to the
mass of phosphorus compounds relative to the total mass of fibers.

[0031]Considering the mass of phosphorus in these types of compounds, the
mass content of phosphorus atoms relative to the mass of fibers is
advantageously between 0.0005% to 1%, especially greater than or equal to
0.01% and even 0.1% and less than or equal to 0.5%.

[0032]The phosphorus compounds described have the drawback of being
hydrophilic, it may be advantageous to add water-repellent agents to
these compounds or with the sizing composition in order to limit the
water uptake of the end product. Silicone-type (polysiloxane)
water-repellent agents are particularly valued. The amount added is
preferably between 0.01% and 1%, especially between 0.05 and 0.2% by
weight.

[0033]A particularly preferred fiber composition within the scope of the
present invention comprises the following constituents in the ranges
defined below, expressed as percentages by weight:

[0034]Silica (SiO2) is a glass network former component. Too large an
amount makes the viscosity of the glass too high for it to be properly
melted, homogenized and refined, whereas too low an amount makes the
glass thermally unstable (it devitrifies too easily on cooling) and
chemically unstable (too prone to attack by moisture). The silica content
is advantageously greater than or equal to 50%, or 55% and even 60% and
less than or equal to 70%.

[0035]Alumina (Al2O3) is also a network former component capable
of significantly increasing the viscosity of the glass. Present in too
large an amount, it also has a negative impact on the solubility in the
pulmonary alveolar fluid. When its content is low, the wet strength is
greatly reduced. For these various reasons, the alumina content is
advantageously greater than or equal to 1% and less than or equal to 5%,
especially 3%.

[0036]The alkaline-earth metal oxides, mainly lime (CaO) and magnesia
(MgO), make it possible to reduce the high-temperature viscosity of the
glass and thus facilitate the processing steps for producing a glass free
from gaseous or solid inclusions. By substitution relative to the alkali
metal oxides, they significantly improve wet strength of the glass, but
on the other hand they favor devitrification, making the fiberizing steps
difficult. The calcium oxide content is therefore advantageously greater
than or equal to 5%, especially 7%, and less than or equal to 10%. As for
the magnesia, its content is preferably less than or equal to 10%, even
5%, and greater than or equal to 1%, or even 2%. Other alkaline-earth
metal oxides such as barium oxide (BaO) or strontium oxide (SrO) may also
be present in the mineral wools according to the invention. Considering
their high cost, they are however advantageously not present (apart from
traces stemming from inevitable impurities of the raw materials).

[0037]The alkali metal oxides, mainly sodium oxide (Na2O) and
potassium oxide (K2O), are particularly useful for reducing the
high-temperature viscosity of the glass and increasing the
devitrification resistance. They prove to be detrimental however to the
aging resistance in a humid environment. The sodium oxide content is, as
a consequence, preferably less than or equal to 18% and greater than or
equal to 14%. The potassium oxide content is advantageously less than or
equal to 5%, or 2% and even 1%, mainly for reasons linked to the
availability of the raw materials.

[0038]Boron oxide (B2O3) is important for reducing the viscosity
of the glass and improving the biosolubility of the fibers. Its presence
tends, moreover, to improve the thermal insulating properties of the
mineral wool, especially by lowering its thermal conductivity coefficient
in its radiative component. Moreover, considering its high cost and its
ability to volatilize at high temperatures, generating harmful emissions
and requiring the production sites to be equipped with fume treatment
plants, the boron oxide content is preferably less than or equal to 8%,
especially 6%, and even 5%. A zero content is preferred in certain
embodiments.

[0039]Iron oxide is limited to a content of less than 5% on account of its
role in coloring the glass, but also in the ability of the glass to
devitrify. A high iron content makes it possible to impart a very high
temperature resistance to mineral wools of the "rock wool" type, but it
makes fiberizing by the internal centrifugation technique difficult or
even impossible in certain cases. The iron oxide content is preferably
less than or equal to 3%, and even 1%.

[0040]Phosphorus oxide (P2O5) may advantageously be used,
especially on account of its beneficial effect on the biosolubility.

[0041]The fibers according to the invention may also contain other oxides,
in amounts by mass that generally do not exceed 3%, or 2% and even 1%.
Among these oxides are the impurities commonly introduced by the natural
or artificial (for example recycled glass, called cullet) batch materials
used in this type of industry (among the most common are TiO2, MnO,
BaO, etc.). Impurities such as ZrO2 are also commonly introduced by
the partial dissolution in the glass of chemical elements deriving from
the refractory materials used in the construction of furnaces. Certain
traces again derive from compounds employed in glass refining: in
particular, the sulphur oxide SO3 that is very commonly employed is
cited. The alkaline-earth metal oxides such as BaO, SrO and/or the alkali
metal oxides such as Li2O may be voluntarily included in the fibers
according to the invention. Considering their cost, it is however
preferable that the fibers according to the invention do not contain
them. These various oxides, on account of their low content, do not in
any case play any particular functional role which may change the manner
in which the fibers according to the invention respond to the problem
posed.

[0042]Another subject of the invention is a method of obtaining the
mineral wools according to the invention, comprising a fiber-forming
step, then a step of introducing, by spraying or impregnation of a
solution, at least one phosphorus compound onto the surface of said
fibers.

[0043]Yet another subject of the invention are the thermal and/or acoustic
insulation products comprising at least one mineral wool according to the
invention, in particular "sandwich" type construction components, in
which the mineral wool makes up an insulating core between two metal (for
example steel or aluminum) facings, these possibly self-supporting
construction components being used in the construction of internal and
external walls, roofs or ceilings.

[0044]The density of the insulation products according to the invention is
preferably between 40 and 150 kg/m3 (this density does not take into
account the mineral wool).

[0045]A final subject of the invention is the use of at least a molecule
in which the phosphorus atom(s) is/are linked to at least one carbon
atom, directly or by means of an oxygen atom, in order to improve the
mechanical properties after aging in a humid environment of the mineral
wools comprising fibers whose chemical composition comprises the
following constituents in the ranges defined below, expressed as
percentages by weight:

[0046]The advantages offered by the glass fibers according to the
invention will be better appreciated through the following examples,
illustrating the present invention without however limiting it.

[0047]A mass of molten glass, of which the chemical composition (expressed
in percentages by weight) is presented in table 1, was obtained by a
method of melting batch materials using, as the main energy source,
electrodes immersed in the glass bath.

[0048]This mass of molten glass was then converted into fibers by an
internal centrifugation method, using a spinner comprising a basket
forming a chamber for receiving the molten glass and a peripheral band
pierced by a multitude of holes. Since the spinner was rotated about a
vertical axis, the molten glass was ejected under the effect of a
centrifugal force and the material escaping from the holes was attenuated
into filaments with the assistance of an attenuating gas stream.

[0049]A size spray ring was placed beneath the spinners so as to spread
the sizing composition uniformly over the glass wool that had just been
formed. The sizing composition was mainly based on phenol-formaldehyde
resin and urea diluted in water before being sprayed onto the fibers.
Other types of sizing composition, in particular those that are
formaldehyde-free, may, of course, also be used, alone or in mixtures.
They may be for example:

[0050]compositions based on an epoxy resin of the glycidyl ether type and
a non-volatile amine hardener (described in Application EP-A-0 369 848),
which may also comprise an accelerator chosen from imidazoles,
imidazolines and mixtures thereof;

[0051]compositions comprising a carboxylic polyacid and a polyol,
preferably combined with a catalyst of the alkali metal salt of a
phosphorus-containing organic acid type (described in Application EP-A-0
990 727);

[0052]compositions comprising one or more compounds incorporating a
carboxylic functional group and/or a β-hydroxyalkylamide functional
group (described in Application WO-A-93/36368);

[0053]compositions incorporating either a carboxylic acid and an
alkanolamine, or a resin previously synthesized from a carboxylic acid
and from an alkanolamine, and a polymer containing a carboxylic acid
group (described in Application EP-A-1 164 163);

[0054]sizing compositions prepared in two steps consisting in mixing an
anhydride and an amine under reactive conditions until the anhydride is
substantially dissolved in the amine and/or has reacted with it, then in
adding water and terminating the reaction (described in Application
EP-A-1 170 265);

[0055]compositions containing a resin that comprises the polymer-free
reaction product of an amine with a first anhydride and a second
anhydride that is different from the first (described in Application
EP-A-1 086 932);

[0056]compositions containing at least one polycarboxylic acid and at
least one polyamine;

[0057]compositions comprising copolymers of carboxylic acid and of
monomers containing alcohol functional groups such as described in
Application US 2005/038193; and

[0058]compositions comprising polyols and polyacids or polyanhydrides such
as maleic acid, described for example in Patent WO 2005/87837 or in U.S.
Pat. No. 6,706,808.

[0060]Aminoplast type resins (melamine-formaldehyde or urea-formaldehyde)
may also be used within the scope of the invention.

[0061]The phosphorus compound was added to the sizing composition, but it
may also be sprayed independently, using a second spray ring. The various
phosphorus compounds used were the following:

[0062]comparative example A did not comprise a phosphorus compound;

[0063]ammonium dihydrogenphosphate, in an amount of 0.5% for comparative
example B1 and 1% for comparative example B2. The use of this phosphorus
compound to improve the aging resistance of the mineral fibers was
especially described in the aforementioned Application WO 97/21636;

[0064]flame retardant with the trade name "EXOLIT OP 550" produced by
Clariant GmbH. Based on a phosphoric polyester type oligomer, it is
especially used as an agent for protecting polyurethanes against fire.
The examples C1 and C2 according to the invention respectively contained
1 and 3% of it relative to the total mass of fibers;

[0065]flame retardant with the trade name "FYROL PNX" sold by Akzo Nobel,
containing 19% of P2O5. It is a phosphoric polyester type
oligomer of formula (3) in which n varies between 2 and 20, R6,
R7 and R8 are ethyl groups and R5 is an ethylene group
(CAS number 184538-58-7) Example D according to the invention contained
1% of it; and

[0066]triethyl phosphonoacetate (TEPA, CAS no. 867-13-0), normally used as
a reaction intermediate. Example E according to the invention contained
1% of it.

[0067]Among other examples of phosphorus compounds according to the
invention are the products BUDIT 341 or 3118F sold by Buddenheim. The
mixture of cyclic phosphonic esters sold under the trademark AMGARD®
CT or CU by Rhodia is also particularly interesting. This product, used
as a fire retardant for polyester-based textiles, has in fact a higher
stability than the product EXOLIT OP 550 at the temperature of the oven,
and thus makes it possible to obtain better mechanical properties before
aging. Its P2O5 content is about 20%.

[0068]The mineral wool thus sized was collected on a belt conveyor
equipped with internal suction boxes which made it possible to keep the
mineral wool in the form of a felt or a sheet on the surface of the
conveyor. The conveyor then passed through an oven where the
polycondensation of the resin of the size took place. The insulation
product manufactured was a panel with a density of around 80 kg/m3.

[0069]The following mechanical tests were undertaken after manufacturing
the product, but before any aging test:

[0070]Compressive Strength Test:

[0071]The compressive strength test, carried out according to the standard
NF EN 826, consisted in applying a compression stress using a loading
machine to a sample with an area measuring 200×200mm2. The
compressive strength was given by the pressure (in kPa) corresponding to
a deformation of 10%.

[0072]Tear Strength Test:

[0073]The tear strength test was carried out according to the principles
of the standard NF EN 1607. It consisted in subjecting a sample with an
area measuring 200×200mm2 stuck between two sheets of wood to
a tensile stress along an axis perpendicular to the surface of the sheets
until the sample ruptured.

[0074]Table 2 contains the results of these various tests, the initial
(that is to say before aging in a humid environment) compressive and tear
strengths being expressed in percentages relative to the reference of the
comparative example A, taken arbitrarily as 100%.

[0075]These results clearly show that the addition of inorganic phosphates
known from the prior art strongly degrades the compressive strength and
tear strength properties of mineral wools, even more so when the content
level of such phosphates is high.

[0076]The addition of phosphorus compounds according to the invention
makes it possible, on the other hand, to minimize the initial losses of
mechanical strength relative to the uncoated products, or even
surprisingly to improve their initial tear strength (example E).

[0077]The sandwich panels comprising a mineral wool whose composition
corresponds to the previously described examples A (comparative), B1
(comparative), C1, C2 and D were subjected to the tear strength test
after aging in a humid environment described in the draft of standard
prEN 14509 "Self-supporting double-skin metal-faced insulating sandwich
panels--Factory made products--Specification". The sandwich panels were
placed in an environmental chamber at 65° C. and 100% relative
humidity for 28 days, the loss of tear strength after aging having not to
exceed 60%. Table 3 describes the results, expressed in terms of loss (in
percent) of tear strength.

[0078]Two mineral wools, one according to example C1, the other according
to the same example but into which a silicone had been injected, in this
case an aqueous solution of polydimethylsiloxane sold under the trademark
Dow Corning® 1581 at a level of 0.1 wt %, were subjected to tests of
partial immersion in water according to the standard NF EN 1609.

[0079]In the absence of silicone, the water uptake was 1.47 kg/m2,
whereas it dropped to 0.4 kg/m2 in the presence of silicone. The
compressive and tear strength results (before and after aging in a humid
environment) are not, on the other hand, affected by the presence of
silicones.

[0080]The use of mineral wools according to the invention makes it
possible therefore to obtain excellent results in terms of aging. The
improvement over the mineral wools free from phosphorus compounds was
spectacular, whereas a clear improvement over the mineral wools coated
with inorganic phosphorus compounds known from the prior art was also
observed.